Fixed condenser



g- 1, 3 o. BLAKE HAL 1,920,346

FIXED CONDENSER Original Filed Dec. 50, 1930 INVENTOR fave BlaKe V' ATRNEYS,

Patented Aug. 1, 1933 UNITED STATES.

FIXED CONDENSER Octave Blake and Haim Beyer, New York, N. Y., assignorsto Cornell Electric Manufacturing Co. Inc., Long Island City, N. Y., aCorporation of New York Original application' December 30, 1930, SerialNo. 505,502. Divided and this application July 19, 1932. Serial No.623,346

1 Claim.

This invention relates in general to small fixed condensers of the woundtype but is not necessarily limited thereto.

One of the objects of this invention is the provision of a novel form offixed non-inductively wound condenser and the method of making the same.

Another object of this invention is to provide a construction and methodof making fixed condensers which are adapted to rapid and cheapmanufacture because of simplicity of construction.

Another object of this invention involves a wax coated condenser withsoft wire supporting leads which are partially enclosed in the waxcoating which acts to make a stronger and more rugged condenser.

An important object of this invention is the provision of fixedcondensers of a type having permanent leads which are constructed so asto provide mounting supports for the condensers.

Another object of this invention is the provision in a self-supportingcondenser of this type of a rigid center core for supporting both theelectrodes of the condenser and the supporting leads in a manner toprevent strains on the electrodes of the condenser when the leads aredeformed.

A further object of this invention is the pro- 30 vision of a woundfixed condenser employing a plurality of longitudinally over-lyingstrips of metal and insulating material shifted transversely in a mannerso that the metal strips project laterally beyond the edges of theinsulating strips.

Another object of this invention is to employ overlying strips of thisnature which have diverging edges near the end so that the first fewturns of the metal strips project beyond the main body of the condenserto permit of connection thereto.

A still further object of this invention is the provision of leadsupporting caps which fit over the projecting edges of the metal stripsand the central mandrel or core and secured to the core by metal tabs onthe caps struck into the core through-the metal strips.

Another object of this invention is the provision of a paper dielectriccondenser with wire leads which provide the sole support for thecondenser.

A still further object of this invention is the provision of anon-inductive condenser having leads which provide the sole supporttherefor.

These and other objects as will appear from the following disclosure aresecured by means of this invention.

This invention resides substantially in the combination, construction,arrangement, relative location of parts, steps and series of steps, allas 00 will be described in greater detail below.

This application is a division of our copending application Serial No.505,502, filed December 30, 1930.

Referring to the drawing,

I Figure 1 is a view of the mandrel and the alternate strips ofinsulating material and metal at the start of the winding operation;

Fig. 2 is a plan view of a condenser wound with the end caps in positionto be fixed in place;

Fig. 3 is an end elevational view of a wound condenser with the caps inplace showing how the turns of one strip of metal are electrically incontact to make a non-inductive condenser; 7

Fig. 4 is a plan view of the condenser with the end caps applied;

Fig. 5 is a plan view of a finished impregnated condenser;

Fig. 6 is a plan view of a modified form of condenser not employing endcaps;

Fig. 7 is another modified form employing metal clips in place of theend caps; and

Fig. 8 is a cross sectional view taken on the line 84 of Fig. 7. 85

It is broadly old to make fixed condensers by winding upon a mandrelstrips of metalseparated by layers of insulating material which aresuper-imposed longitudinally and transversely in alignment. Condensersof this type are usually provided with leads which are connected to themetal strips without the provision of means for supporting the leads sothat, as they are bent. there is a tendency .for the leads to tear themetal strips ruining the condenser.

The condenser of this invention overcomes this major difficulty and, inaddition, has many other features of advantages over prior knownconstructions.

Referring to the drawing there is shown in Figure 1, a core or mandrelmade of suitable insulating material such as fiber, bakelite,impregnated wood and the like. This core, as shown in the form of around rod, scored at separated points, as indicated at 2, to provide anumber of cores 1 of the desired size. The core is mounted in a suitablewinding machine so that the first section. 1 is exposed for winding. Themetal strips 3 and 5 are constructed of any suitable, U thin metal, suchas tin foil. A strip of thin, in-

For a suitable distance from the end of these strips where the windingbegins, the strips are wider. As shown in this figure, these stripsgradually diverge from the point '7 to the end, while the remainder ofthe strips is of uniform width. It is of course apparent, that the widerend from the point '7 could be of uniform width and joined to thenarrower portion of the strips by a shoulder. It is immaterial how theabove result is secured just so long as the first few turns of the metalstrips extend farther beyond the main body of the winding than theremaining turns. In other words, although all of the turns of the metalstrips project beyond the insulating strips, the first few turns extenda greater distance than the remaining turns.

The mandrel or core is rotated causing the superimposed layers to windup thereon until the desired amount of material has been wound toprovide a condenser of a desired capacity. The strips are then out offand the first section v 1 of the core is broken off at the scoring 2.

The core may then be advanced'to expose the next section 1 for winding.The condenser is in the state indicated in Fig. 2 when the winding iscompleted, the layer of paper 6 forming the last turn to insulate thestrip 5 from exterior contact. At the left, the first few turns of themetal strip 3 project as shown at 5 and, at the right the first fewturns of the metal strip 3 project as shown at 3. The caps 8 are ofmetal and are provided with soft drawn, copper wire leads 9' which aresoldered thereto. In the form disclosed for illustration, the leadsextend through a center hole in the caps and are soldered on theinterior wall thereof.

As shown in Fig. 4 the caps are slipped over the ends of the core 1 andover the projecting turns of the metal strips 5 and 3. Fourdiametrically opposed square punch holes are then made in the capstriking up metal tabs which pass through the projecting ends 5 and 3 ofthe metal strips and into the core 1. This simple operation serves tosecure the caps in place and to effect permanent electrical contact withthe metal strips of the condenser without soldering. This is animportant feature of the invention since it is well known that it isdiflicult to secure the leads of a condenser to the metal strips bysoldering or indeed by any present known method. In addition, therelatively stiff leads quickly tear'the thin metal strips ruining thecondenser. A very important feature of this invention is now apparent.Soft drawn copper leads 9 soldered to the caps, may be bent to anysuitable shape without placing any strain on the plates of the condensersince the core directly takes these strains. For this reason, the leads9 may be employed as the sole support for the condenser. Another featureof this invention is apparent from Fig. 3. As the condenser builds upduring the winding operation, the projecting edges of the metalstrips'form into substantially,

concentric cylinders. When the winding of the condenser is finished,these projecting edges may be bent downwardly so that all the layers ofeach strip are forced into electrical contact; the innermost turnscontacting with the projecting edges 3 and 5. The result is, that allthe turns of each plate of the condenser are in electrical contactproducing a non-inductive fixed condenser.

In the case of the small condensers, all the plate turns are includedunder the end caps to insure interconnection between the plates. In thecase of the larger condensers'only a few of the turns of each plate areincluded under the caps, and the remaining turns are folded down overeach other in succession as indicated in Fig. 3.

The unit of Fig. 5 is then immersed in a suitable insulating compound sothat it is completely encased thereby, as indicated at 100 in Fig. 5. Asa result moisture cannot get into the condenser to reduce its dielectricresistance and change its capacity.

In the modified arrangement shown in Fig. 6, the condenser is wound tothe point indicated in Fig. 2 in the same manner as already described.In this form metal caps are not employed. The ends of the core 1 areprovided with holes 11 through which the ends of the leads 12 and 13extend. The inner ends of these leads are wound around the projectingedges 3 and 5 of the metal strips to form the turns 13. This provides acontact between the leads 12 and 13' and the metal plates. denser iscoated with an insulating compound as described before. The insulatingcoating which may be of wax thoroughly protects the condenser and alsoacts to strengthen the wire leads. It will be noted that, as in the caseof the first form described, the core 1 takes all the strains when leads12 and 13 are bent.

The modified arrangements in Figs. '7 and 8 likewise comprise the woundmember as shown in Fig. 2. In this case, instead ofemploying caps,U-shaped clips 14 are provided which support the leads 15. These capsslip over the end of the core 11' which, in this case, is rectangular inform and are secured thereto by punched outtabs as indicated at 16.These tabs extend as before through the projecting edges of the metalstrips 3 and 5 into the core 11'. Here, likewise, the strains are takenby the core. This 4 condenser is also coated with a suitableimpregfacture and adapted to rapid and cheap production without in anyway sacrificing the quality thereof. Indeed by this construction, a verydesirable and strong condenser results. The leads from thecondenserare'secured thereto to provide a support for the condenser and may Theentire conbe deformed without exerting any strains on' the thin metalstrips which comprise the condenser. The member which is shown as a coreneed not necessarily be a central core since the advantages of thisconstruction can be secured without having the member 1 at the center ofthe condenser.

Since then this invention resides in certain principles of constructionand methods of procedure, it is not desired to be limited to thedisclosure as given for purposes of illustration but rather to the scopeof the invention as it is defined in the appended claim.

What we seek to secure by United States Letters Patent is:

A non-inductive condenser comprising a supporting core, a pair of metalstrips interleaved with insulating strips wound on said core with oneedge of each of the metal strips projecting beyond opposite sides of theinsulating strips, a metal cap secured to the core at each end incontact with the first few turns of the projecting edge of the metalstrip, the edges of the

